Why did I lose all the volume on my buttocks after a month of BBL?

Had a BBL a month ago and I notice the size of my buttocks are back to how it was before surgery " small" not flat still a little round but not even close to my expectations, the size after surgery was not that big either but it was still noticeable, I'm assuming that this was just inflammation caused for the surgery, but is my size gonna keep decreasing? Or there's any way I can get a touch up without my fat since I have none after the liposuction?